The presence of arsenic in its various chemical forms as an impurity in products or feed stocks can be detrimental to the use of such products or feed stocks. For example, the presence of arsenic in even small quantities is undesirable in industrial gases, hydrocarbon feed stocks, fuels, natural gases, etc. Also, the presence of arsenic in industrial effluent streams such as off-gases from refinery and gasification processes and the like may create health hazards and/or might be subject to environmental controls.
Most crude oils and shale oils contain arsenic in one form or another. When such oils are cracked, fractionated or otherwise treated to separate petroleum fractions, the resulting petroleum fractions will contain arsenic. When such petroleum fractions are to be subjected to combustion or further treatment, particularly when the treatment involves a catalyst comprising a noble metal, the presence of arsenic is harmful since it can poison the nobel metal catalyst. The presence of arsenic is particularly harmful in hydrocarbon fractions which are subjected to further processing in the presence of a catalyst comprising palladium or platinum. Various methods of removing arsenic impurities, especially arsine, from gaseous streams have been developed, but improved processes are still desired.